1. Field of the Invention
The present invention relates to a method of fabricating a flat panel display. In particular, the present invention relates to a method of fabricating a thin film transistor (TFT) flat panel display.
2. Description of the Related Art
FIGS. 1A to 1D illustrate the conventional method of fabricating a TFT liquid crystal flat panel display. Referring to FIG. 1A, a gate electrode 2 is formed on a substrate 1, and then an insulating layer 3 is formed to cover the gate electrode 2. Then, an amorphous silicon layer 40 and a silicon nitride 50 are formed on the insulating layer 3. Referring to FIG. 1B, an etching stopper 5 is formed by etching the silicon nitride 50. Referring to FIG. 1C, a doping silicon layer 6 (to be n+ doped amorphous silicon) is formed on the etching stopper 5 and the amorphous silicon 40. Referring to FIG. 1D, a metal layer is formed on the substrate 1, and then is etched to form a source electrode 7 and a drain electrode 8. Finally, a passivation layer 9 is formed. In the etching process, part of the metal layer and the doping silicon layer 6 are removed, and the etching stopper 5 is used for preventing the amorphous silicon layer 40 form etching damage.
The conventional method can be used to fabricate TFT flat displays; however it still has the spaces for improvement and simplification.
In order to improve and simplify the above-mentioned conventional manufacturing steps, the present invention proposes a new method of fabricating a TFT flat panel display, merely requiring four mask processes.
The present invention proposes a method of fabricating a TFT flat display is characterized by: (1) using the first mask process for patterning the first conductive layer/gate insulating layer/amorphous silicon layer of the TFT, (2) using the second mask process for defining the passivation layer and the etching stopper, (3) using the third mask process for forming the Source/Drain, and (4) using the fourth mask process for forming the pixel electrode, whereby simplifying the fabricating process of the TFT flat panel display.